Radial buttress dam



July 10, 1 934. c R OLBERG 1,965,988

RADIAL BUTTRES S DAM Filed March 12, 1929 3 Sheets-Sheet l July 10; 1934. c. R. OLBERG 1,965,988

RADIAL BUTTRESS DAM Filed March 12,- 1929 3 Sheets-Sheet 2 July 10, 1934. c, R LBE 1,965,988

RADIAL BUTTRESS DAM Filed March 12-, 1929 3 Sheets-Sheet 3 l 45 important advantage that it Patented July 10, 1934 UNITED STATES PATENT OFFICE 20 Claims.

.This invention relates to .masonry dams of the dome type and has for its principal object the provision of a dam which will have all of the benefits of what is known .as a multiple dome dam while requiring less excavation to permit symmetry of the domes and will also be better from an engineering standpoint in that the thrust of the side domes will be presented to the canyon wall more nearly normal than is possible with multi- 1'0 ple dome dams in which the thrust, because of the parallel buttresses, is parallel to the walls.

A further object of the present invention is the combination of such a dam as has just been described with a gravity base. The practical limit at the present time of a parallel buttress multiple dome dam is roughly somewhat less than four hundred feet probably about 350 feet. The radial buttress gravity domedam, the provision of which is an important feature of the present invention,

may be carried to a height as great as the Washington Monument, by having a gravity section of two hundred feet or so.

Further objects of the invention pertain primarily to details such for example as the provision of shrinkage joints to permit shrinkage stress which would otherwise produce undesirable cracks in the buttresses along the line of the principal stresses, and the provision of an optional curved surface rising from the pool basin to receive the spillway water and prevent pounding.

In my copending application Serial No. 63,735, -filed October 20, 1925, now Patent No. 1,708,452 dated April 9, 1929, I have shown a multiple dome dam in which the buttress piers are parallel. A

I dam of this kind is a great improvement over previous dams and I find that by bringing the domes together at the river bed I not only eliminate a large amount of concrete in the base of the intermediate buttresses but I also avoid a great amount of excavation in the canyon walls along the outer or side domes. The result of this construction is to form an unusual downstream curve which however not only does not effect the stability of the dam but has the rather facilitates the construction of the roadway over the dam and in addition presents an attractive appearance. The dam thus built is quite like my previous dam as will be noted by a comparison of the present 7; drawings with those of the patent cited, the most marked difference being that the center lines of the buttresses and of the domes converge at a center point upstream from the dam and that the flare which is quite noticeable at the rear of each i buttress of the patent is nearly eliminated in the present structure not only greatly reducing the amount of concrete required as compared with that needed for the parallel type but also providing a buttress of more nearly constant width. Inasmuch as the toe of the buttress will ordinarily be at a higher elevation than the heel, the bases will have a tendency to climb the sides of the canyon, thus having a locking function.

In the drawings:

Figure 1 is aplan view of a radial buttress dam 65 not over 350 feet high. The contour lines represent fifty foot elevations.

Figure 2 is an elevation of the dam shown in Figure 1.

Figure 3 is a section thru that dam.

Figure 4 is an elevation of a buttress -i'llus trating the location of the shrinkage joints.

Figure 5 is a section thru a joint.

Figure 6 is a plan view of a dam of greater height than 350 feet;

Figure 7 is an elevation of the dam shown in Figure 6.

Figure 8 is a central vertical section of the dam of Figure .6.

Figure 9 is a "horizontal section taken on line 9-9 of Figure 7.

Considering first the simpler dam illustrated inFigures 1, 2 and 3, A represents the approximate ground line, B any one of the three ,central domes, C the piers between adjacent domes,

.D the roadway, E any one of the four arches of "the multiple arch dam type, two on each side, which fill out the gap between each end dome and the canyon wall as best seen in Figure 2. The individual domes B are substantially as fully described in my cited patent consisting of an ellipsoidal section, the walls of which increase in thickness from the crest to the bottom, the upstream and downstream faces of each dome, numbered 10 and 11 in the drawings, 'bei g surfaces of generation each generatrix being a smooth curve and the axis of generation being tilted at approximately 45.

It will be noted from the plan view, Figure 1, 1 that the domes areldrawn together at the river bed which causes the entire dam to curve downstream. This downstream curving narrows the flare at the "bottom of each radial buttress C so that as best seen in Figure 2. the width of 5 the buttress is .fairly constant, decreasing but gradually from the foundation at numeral '12 to the narrowest portion 13 which is .at the same level as the widest portions of the adjacent domes. The domes are likewise radial, that is the center line of 70 the fore-and-aft centerli nes 51 of any two domes will converge toward an upstream point. The horizontal axis of the dam is transverse as usual but because the dam is curved downstream, the horizontal axes of the end sections, which are tangent to the horizontal axis of the center or dome portion, are curved upstream. While not invariably the case usually the toe 14 of the buttress will be at a higher elevation than the heel 15 this being a decided advantage in keying the buttress into the foundation and as a preventive against sliding movement of the dam in a downstream direction. The downstream curve of the dam is along a circular arc lending grace to the structure and being very pleasing to the eye after one becomes accustomed to this unusual feature. The downstream circular arc lends itself better to the construction of spillways should they be provided at the ends of the dam and also facilitates in no small degree the building of the road leading over the dam.

It is always advisable to have the domes as symmetrical as possible so as not to affect the statical condition of the buttresses C but the provision of the radial buttresses C requires much less excavation to secure this desired symmetry than is needed when the piers are parallel to each other and furthermore since the horizontal axis of the dam is a circular arc with the abutments either a part of the arc or tangent to it the domes B will fit the dam site much more readily than with the older form of multiple dam. Furthermore the thrust of the outer domes against the canyon walls will be more nearly at right angles to the face. of the wall than with the straight buttresses wherein the thrust would naturally bev parallel to the buttresses and the walls.

Referring more particularly to the preferred form in Figures 6 to 9 this dam in addition to the domes and piers as in the previous dam adds the important gravity section. Referring particularly to Figure 8 the gravity section is of huge mass having the previously used faces and 21 the pressure at the bottom due to the dome action thru the section being transferred to the gravity section thru the face 21 while the component .of the weight of the dome is transferred to the gravity section 22 thru the face 20. That portion of the domes above the faces 20 and 21 is substantially identical with the domes B and with the domes of my cited patent.

The gravity section has a rear face 24 tangent j to the intrados l1 and forming a pool 25 which actsras a water cushion for the water 26 coming 'over the spillway opening 27 which is preferably .made in at least three portions and here shown in Figure 6 as being four in number. The curved surface 30 is optional but when used will eliminate pounding. The small dam or weir 31 is of such height as to impound sufficient water to f yield the cushioning effect desired.

' The flare of the buttresses is continued from the top of the dam down until the flares intersect and below such point of intersection the base is jsolid. A horizontal section of the dam below the domes and above the solid face will show the buttresses as parallel lines which join at the rear in a circular arc. A vertical section thru the .crown of the dome at the base shows the intrados extended as a vertical circular arc so the space below the dome and between the buttresses over the solid base is an inverted spherical dome in the rear. The domes end as indicated in the drawings just'below where they break over into thespherical sections.

In Figure 4 I have indicated the shrinkage joints 40 and 41. These joints are located along the line of the principal stress and are provided to allow the operation of the shrinkage stress that might otherwise produce undesirable cracks in the buttresses. As illustrated in Figure 5 the joints are exactly alike consisting of a central section 42 and two side sections 43 each of the la ter being of a length equal approximately to one-fourth of the thickness of the buttress from side to side. The face 42 is offset from the faces 43 (which latter lie in a single plane) by approximately six inches, the connecting faces 44 being at an angle of 45 to the adjacent faces 42 and 43. The faces are all painted and preferably each joint is provided with a 90 groove about one and one-half inches deep as indicated at 45 at each side 46 of the buttresses. The dot and dash line 47 of Figure 4 represents the center line of the roadway. The similar dot and dash lines 49 of Figure 6 represent the center lines of the -buttresses, these lines meeting at a point 50 in point.

3. A masonry dam consisting of a curved top section, a series of domes located against and upstream from said top section, the transverse axis of said top section being downstream so that the two ends of the dam are upstream from middle portion of the dam, and the thrust of the side domes consequently is toward the canyon walls.

4. A dam comprising a plurality of radial domes having a horizontal axis which is curved up-- stream at its two ends and having a section tangent to the horizontal axis of the domes on each side to fill the gaps between the end domes and the canyon walls.

5. In a dam, a buttress having a shrinkage.

joint located along the line of principal stress, said joint extending from side to side of the buttress.

6. The device of claim 5 in which the joint slopes upwardly and rearwardly and a second similarly sloping joint is roughly parallel to the first joint and of less height.

'7. The device of claim 5 in which each joint consists of three faces the central section being slightly offset with respect to an adjacent section.

8. A dam comprising a plurality of domes, a buttress between each two domes, the center lines of the buttresses meeting in a point upstream from the dam, the central dome having spillway gates near its crown, said section also having a curved surface rising from its base upon which the water passing thru the spillway gates is allowed to impinge to prevent pounding.

9. A masonry dam consisting of at least two buttresses and at least three domes, each of the two buttresses being between two domes, the center lines of the two buttresses and of the side domes each being radial with respect to an upstream point. I

buttresses and at least three domes, each of the two buttresses being between two domes, the center lines of the two buttresses and. of the side domes each being radial with respect to an upstream point in which the several upstream points coincide.

11. A masonry dam made up of a series of two or more domes of which two are side domes, the center lines of each side dome being radial to an upstream point so as to cause the thrust on the side dome to be directed toward downstream points on opposite canyon walls.

12. The device of claim 11 in which there are three domes having between them two buttresses the center line of each also being radial to an upstream point and in which the three domes are brought together at the river bed, requiring less excavation to permit symmetry than in a parallel buttress dome dam, and also avoiding a great amount of excavation in the canyon walls along the outer or side domes.

13. A masonry dam including a plurality of domes and a plurality of alternate buttresses, the toes being at a higher elevation than the heels, the center lines of the domes and also of the buttresses converging at a single point upstream from the dam, the flares at the rear of the butt-resses being nearly eliminated by such construction, whereby the buttresses are of nearly constant width and have a tendency to climb the sides of the canyon thus having a looking or keying function.

14. A masonry dam consisting of a gravity section and a superposed dome section, the dome section having a downstream surface of ellipsoidal form and the gravity section having a similar tangent surface.

15. The dam of claim 14 in which the dome has its down-stream surface a surface of generation about an axis tilted at about 45 and the gravity section increases in front to rear center section from the bottom of the dome to the heel of the gravity section.

16. A masonry dam for a canyon comprising a plurality of symmetrical non-spherical domes, the domes being cramped within the canyon, that 'is, the projections of the fore-and-aft centerlines of the domes upon a horizontal plane converging toward an upstream point, thereby lessening the amount of excavation needed.

1'7. A dam comprising a center section having a down-stream curve and two side sections each of which is a continuation of the center section and directed slightly upstream from the center section, said center section comprising a plurality of domes each having the horizontal projection of its sloping major axis radial with respect to an upstream point, and said side sections filling the gaps between the domes of the center section and the canyon walls.

18. A canyon dam consisting of a center section comprising a plurality of non-spherical domes with their centerlines converging toward an upstream point and two side sections each extending from the domes to the proximate canyon wall, the junctions of the canyon walls and the side sections being upstream from the junctions of the side sections with the center section.

19. A masonry dam for a canyon in which the depth of the impounded water shall be in excess of three hundred feet, comprising a plurality of buttresses having their centerlines converging toward an upstream point, an ellipsoidal dome on each side of each buttress and integral therewith. each dome having its upstream and its downstream face, surfaces of generation about an axis of generation approximately 45 to horizontal and to vertical, the horizontal projections of said axes converging toward an upstream point, and a gravity portion beneath the buttresses and domes and formed by the continuation of the flares of the buttresses until they intersect, a horizontal section thru the dam below the domes and above the solid portion showing the buttresses as substantially parallel lines joined at the rear by a smooth curve substantially arcuate, such construction materially narrowing the flare of the buttresses above the level of the bottoms of the domes as compared with the buttresses of a multiple dome dam with parallel buttresses.

20. A dam including a dome mounted upon a gravity section, the inner face of the vertical section of which is substantially elliptical with the major axis of the ellipse horizontal and a Weir extending upwardly from the rear of the gravity section to form a pool.

CHARLES R. OLBERG. 

